U.S. patent application number 11/299742 was filed with the patent office on 2006-06-15 for energy storage device, module thereof and electric vehicle using the same.
Invention is credited to Juichi Arai, Mituru Kobayashi, Yoshiaki Kumashiro, Takahiro Yamaki, Masanori Yoshikawa.
Application Number | 20060124973 11/299742 |
Document ID | / |
Family ID | 36582788 |
Filed Date | 2006-06-15 |
United States Patent
Application |
20060124973 |
Kind Code |
A1 |
Arai; Juichi ; et
al. |
June 15, 2006 |
Energy storage device, module thereof and electric vehicle using
the same
Abstract
An object of the present invention is to provide an energy
storage device excellent in input/output characteristics at low
temperatures, a module thereof and a vehicle using the module. The
present invention provides an energy storage device comprising: a
positive electrode having a region where a reaction accompanied by
charge exchange occurs; a negative electrode having a region where
a reaction accompanied by charge exchange occurs; a separator
electrically separating the positive and negative electrodes and
allowing mobile ions to pass therethrough; an electrolytic solution
having an aprotic nonaqueous solvent comprising the mobile ions;
and a region in at least one of the positive and negative
electrodes where a charge adsorbing/desorbing reaction occurs.
Inventors: |
Arai; Juichi; (Shirosato,
JP) ; Kumashiro; Yoshiaki; (Mito, JP) ;
Yoshikawa; Masanori; (Hitachinaka, JP) ; Kobayashi;
Mituru; (Hitachiota, JP) ; Yamaki; Takahiro;
(Hitachinaka, JP) |
Correspondence
Address: |
ANTONELLI, TERRY, STOUT & KRAUS, LLP
1300 NORTH SEVENTEENTH STREET
SUITE 1800
ARLINGTON
VA
22209-3873
US
|
Family ID: |
36582788 |
Appl. No.: |
11/299742 |
Filed: |
December 13, 2005 |
Current U.S.
Class: |
257/223 |
Current CPC
Class: |
B60L 2240/545 20130101;
H01M 2300/0042 20130101; H01G 11/10 20130101; H01M 10/0567
20130101; B60L 2240/12 20130101; H01G 9/22 20130101; Y02E 60/10
20130101; B82Y 30/00 20130101; H01M 4/505 20130101; Y02E 60/13
20130101; B60L 58/18 20190201; B60L 2210/40 20130101; B60L 50/66
20190201; B60L 2240/549 20130101; B60K 6/28 20130101; B60L 50/64
20190201; Y02T 10/62 20130101; Y02T 90/40 20130101; H01M 10/052
20130101; Y02T 10/70 20130101; H01M 4/525 20130101; B60L 50/16
20190201; B60L 2240/547 20130101; B60K 6/48 20130101; H01M 10/0569
20130101; H01G 11/60 20130101; Y02T 10/7072 20130101; Y02T 10/72
20130101; H01G 9/035 20130101; B60K 6/32 20130101; H01G 11/46
20130101; H01G 11/06 20130101 |
Class at
Publication: |
257/223 |
International
Class: |
H01L 27/148 20060101
H01L027/148 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 14, 2004 |
JP |
2004-360659 |
Claims
1. An energy storage device comprising: a positive electrode having
a region where a reaction accompanied by charge exchange occurs; a
negative electrode having a region where a reaction accompanied by
charge exchange occurs; a separator electrically separating said
positive and negative electrodes from each other and allowing
mobile ions to pass therethrough; an electrolytic solution having
an aprotic nonaqueous solvent comprising said mobile ions; and a
region in at least one of said positive and negative electrodes
where a charge adsorbing/desorbing reaction occurs.
2. The energy storage device according to claim 1, wherein: said
regions where the reaction accompanied by charge exchange occurs
are formed in a laminated manner in current collectors; and said
region where the charge adsorbing/desorbing reaction occurs is
formed in a laminated manner on the surface of said region where
the reaction accompanied by charge exchange occurs.
3. The energy storage device according to claim 1, wherein said
region where the reaction accompanied by charge exchange occurs and
said region where the charge adsorbing/desorbing reaction occurs
are formed on the surfaces of the current collectors in a mixed
manner or in an alternate manner.
4. The energy storage device according to claim 1, wherein said
nonaqueous solvent comprises at least one solvent selected from the
group consisting of solvents represented by the following formulas
(1) to (20): a cyclic carbonate solvent represented by: ##STR1##
wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 each represent a
hydrogen, fluorine or chlorine atom; or alternatively a C.sub.1-3
alkyl group, an allyl group or an acyl group; or alternatively a
fluorinated alkyl, allyl or acyl group; and R.sub.1, R.sub.2,
R.sub.3 and R.sub.4 may be the same or different from each other; a
chain carbonate solvent represented by: ##STR2## wherein R.sub.5
and R.sub.6 each represent a hydrogen, fluorine or chlorine atom;
or alternatively a C.sub.1-3 alkyl group or a fluorinated alkyl
group; and R.sub.5 and R.sub.6 may be the same or different from
each other; a chain ester solvent represented by: ##STR3## wherein
R.sub.7 and R.sub.8 each represent a hydrogen, fluorine or chlorine
atom; or alternatively a C.sub.1-3 alkyl group or a fluorinated
alkyl group; and R.sub.7 and R.sub.8 may be the same or different
from each other; a lactone derivative represented by: ##STR4##
wherein R.sub.9, R.sub.10, R.sub.11, R.sub.12, R.sub.13 and
R.sub.14 each represent a hydrogen, fluorine or chlorine atom; or
alternatively a C.sub.1-3 alkyl group; or alternatively a
fluorinated alkyl, allyl or acyl group; and R.sub.9, R.sub.10,
R.sub.11, R.sub.12, R.sub.13 and R.sub.14 may be the same or
different from each other; a dioxolane derivative represented by:
##STR5## wherein R.sub.15, R.sub.16, R.sub.17, R.sub.18, R.sub.19
and R.sub.20 each represent a hydrogen, fluorine or chlorine atom;
or alternatively a C.sub.1-3 alkyl group or a fluorinated alkyl
group; and R.sub.15, R.sub.16, R.sub.17, R.sub.18, R.sub.19 and
R.sub.20 may be the same or different from each other; a chain
ether derivative represented by: ##STR6## wherein n is an integer
of 1 to 10, R.sub.21 is methylene, and R.sub.22 is a hydrogen,
fluorine or chlorine atom; or alternatively a C.sub.1-3 alkyl group
or a fluorinated alkyl group; a dioxolane derivative represented
by: ##STR7## wherein R.sub.23, R.sub.24, R.sub.25, R.sub.26,
R.sub.27, R.sub.28, R.sub.29 and R.sub.30 each represent a
hydrogen, fluorine or chlorine atom; or alternatively a C.sub.1-3
alkyl group or a fluorinated alkyl group; and R.sub.23, R.sub.24,
R.sub.25, R.sub.26, R.sub.27, R.sub.28, R.sub.29 and R.sub.30 may
be the same or different from each other; a chain ether derivative
represented by: ##STR8## wherein n is an integer of 1 to 10,
R.sub.31 and R.sub.32 each represent a hydrogen, fluorine or
chlorine atom; or alternatively a C.sub.1-3 alkyl group or a
fluorinated alkyl group; and R.sub.31 and R.sub.32 may be the same
or different from each other; a cyclopentane derivative represented
by: ##STR9## wherein R.sub.31, R.sub.32, R.sub.33, R.sub.34,
R.sub.35, R.sub.36, R.sub.37, R.sub.38, R.sub.39 and R.sub.40 each
represent a hydrogen, fluorine or chlorine atom; or alternatively a
C.sub.1-3 alkyl group or a fluorinated alkyl group; and R.sub.31,
R.sub.32, R.sub.33, R.sub.34, R.sub.35, R.sub.36, R.sub.37,
R.sub.38, R.sub.39 and R.sub.40 may be the same or different from
each other; an alkane represented by: R.sub.41--R.sub.42 (Formula
10) wherein R.sub.41 and R.sub.42 each represent a hydrogen,
fluorine or chlorine atom; or alternatively a C.sub.1-3 alkyl group
or a fluorinated alkyl group; and R.sub.41 and R.sub.42 may be the
same or different from each other; a 1,3-dioxo-4,5-1en-2-one
derivative represented by: ##STR10## wherein R.sub.43 and R.sub.44
each represent a hydrogen, fluorine, chlorine atom; or
alternatively a C.sub.1-3 alkyl group or a fluorinated alkyl group;
and R.sub.43 and R.sub.44 may be the same or different from each
other; a phenyl derivative represented by: ##STR11## wherein
R.sub.45, R.sub.46, R.sub.47, R.sub.48, R.sub.49, R.sub.50,
R.sub.51, R.sub.52, R.sub.53 and R.sub.54 each represent a
hydrogen, fluorine or chlorine atom; or alternatively a C.sub.1-3
alkyl group or a fluorinated alkyl group; and R.sub.45, R.sub.46,
R.sub.47, R.sub.48, R.sub.49, R.sub.50, R.sub.51, R.sub.52,
R.sub.53 and R.sub.54 may be the same or different from each other;
an ethylene sulfite derivative represented by: ##STR12## wherein
R.sub.55, R.sub.56, R.sub.57 and R.sub.58 each represent a
hydrogen, fluorine or chlorine atom; or alternatively a C.sub.1-3
alkyl group, an allyl group or an acyl group; or alternatively a
fluorinated alkyl, allyl or acyl group; and R.sub.55, R.sub.56,
R.sub.57 and R.sub.58 may be the same or different from each other;
a propane sultone derivative represented by ##STR13## wherein
R.sub.59, R.sub.60, R.sub.61, R.sub.62, R.sub.63 and R.sub.64 each
represent a hydrogen, fluorine or chlorine atom; or alternatively a
C.sub.1-3 alkyl group, an allyl group or an acyl group; or
alternatively a fluorinated alkyl, allyl or acyl group; and
R.sub.59, R.sub.60, R.sub.61, R.sub.62, R.sub.63 and R.sub.64 may
be the same or different from each other; a disulfide derivative
represented by R.sub.65--S--S--R.sub.66 (Formula 15) wherein
R.sub.65 and R66 each represent a hydrogen, fluorine or chlorine
atom; or alternatively a C.sub.1-3 alkyl group, an allyl group or
an acyl group; or alternatively a fluorinated alkyl, allyl, acyl,
phenyl, benzyl, diphenyl or terphenyl group; or alternatively a
partially fluorinated phenyl, benzyl, diphenyl or terphenyl group;
or alternatively a partially alkylated, allylated or acylated
phenyl, benzyl, diphenyl or terphenyl group; and R.sub.65 and
R.sub.66 may be the same or different from each other; a benzene
derivative represented by: ##STR14## wherein R.sub.67, R.sub.68,
R.sub.69, R.sub.70, R.sub.71 and R.sub.72 each represent a
hydrogen, fluorine or chlorine atom; or alternatively a C.sub.1-3
alkyl group, an allyl group, an acyl group or an alkoxy group; or
alternatively a fluorinated alkyl, allyl, acyl or alkoxy group; and
R.sub.67, R.sub.68, R.sub.69, R.sub.70, R.sub.71, and R.sub.72 may
be the same or different from each other; a pyridine derivative
represented by: ##STR15## wherein R.sub.73, R.sub.74, R.sub.75,
R.sub.76 and R.sub.77 each represent a hydrogen, fluorine or
chlorine atom; or alternatively a C.sub.1-3 alkyl group, an allyl
group, an acyl group or an alkoxy group; or alternatively a
fluorinated alkyl, allyl, acyl or alkoxy group; and R.sub.73,
R.sub.74, R.sub.75, R.sub.76 and R.sub.77 may be the same or
different from each other; a chain phosphazene derivative
represented by: ##STR16## wherein R.sub.78, R.sub.79, R.sub.80 and
R.sub.81 each represent a C.sub.1-3 alkyl group, an allyl group, an
acyl group or an alkoxy group; or alternatively a fluorinated
alkyl, allyl, acyl or alkoxy group; and R.sub.78, R.sub.79,
R.sub.80 and R.sub.81 may be the same or different from each other;
a cyclic phosphazene derivative represented by: ##STR17## wherein
R.sub.82, R.sub.83, R.sub.84, R.sub.85, R.sub.86 and R.sub.87 each
represent a C.sub.1-3 alkyl group, an allyl group, an acyl group or
an alkoxy group; or alternatively a fluorinated alkyl, allyl, acyl
or alkoxy group; and R.sub.82, R.sub.83, R.sub.84, R.sub.85,
R.sub.86 and R.sub.87 may be the same or different from each other;
and a phosphate derivative represented by: ##STR18## wherein
R.sub.88, R.sub.89 and R.sub.90 each represent a C.sub.1-3 alkyl
group or a fluorinated alkyl group; and R.sub.88, R.sub.89 and
R.sub.90 may be the same or different from each other.
5. The energy storage device according to claim 1, wherein said
region where the reaction accompanied by charge exchange occurs in
said positive electrode comprises at least one electric energy
storing/releasing material selected from the group consisting of
LiNi.sub.xMn.sub.yCo.sub.zO.sub.2 (with the proviso that x+y+z=1),
a composite oxide comprising Li and one or more transition metals
such as Co, Ni, Mn and Fe, and an olivine-structured phosphate
compound represented by LiMePO.sub.4 (Me being Fe, Co or Cr).
6. The energy storage device according to claim 1, wherein, said
region where the reaction accompanied by charge exchange occurs in
said negative electrode comprises at least one electric energy
storing/releasing material selected from the group consisting of a
carbonaceous material capable of occluding/releasing lithium;
lithium metal; a lithium alloy; silicon; silicon oxides; tin; tin
oxides; and composite materials composed of the carbonaceous
material and one or more of lithium metal, a lithium alloy,
silicon, silicon oxides, tin and tin oxides.
7. The energy storage device according to claim 1, wherein said
region where the charge adsorbing/desorbing reaction occurs
comprises at least one selected from the group consisting of
activated carbon, carbon nanotube, expanded graphite, ruthenium
oxide, titanium oxide, and composite materials composed of the
activated carbon and one or more of carbon nanotube, expanded
graphite, ruthenium oxide and titanium oxide.
8. The energy storage device according to claim 1, wherein said
electrolytic solution comprises at least one solute selected from
the group consisting of LiPF.sub.6, LiAsF.sub.6, LiBF.sub.4,
LiSO.sub.2CF.sub.3, LiN[SO.sub.2CF.sub.3].sub.2,
LiN[SO.sub.2CF.sub.2CF.sub.3].sub.2, LiC[SO.sub.2CF.sub.3].sub.3,
LiC[SO.sub.2CF.sub.2CF.sub.3].sub.2, LiB[OCOCF.sub.3].sub.4,
LiB[OCOCF.sub.2CF.sub.3].sub.4, LiI, LiBr, LiCl, NaPF.sub.6,
NaAsF.sub.6, NaBF.sub.4, NaSO.sub.2CF.sub.3,
NaN[SO.sub.2CF.sub.3].sub.2, NaN[SO.sub.2CF.sub.2CF.sub.3].sub.2,
NaC[SO.sub.2CF.sub.3].sub.3, NaC[SO.sub.2CF.sub.2CF.sub.3].sub.2,
NaB[OCOCF.sub.3].sub.4, NaB[OCOCF.sub.2CF.sub.3].sub.4, Nal, NaBr
and NaCl.
9. The energy storage device according to claim 1, wherein said
electrolytic solution comprises at least one selected from the
group consisting of ethylene carbonate (EC), propylene carbonate
(PC) and butylene carbonate (BC), at least one selected from the
group consisting of dimethyl carbonate (DMC), ethyl methyl
carbonate (EMC) and diethyl carbonate (DEC), and at least one
selected from the group consisting of LiPF.sub.6, LiBF.sub.4,
LiSO.sub.2CF.sub.3, LiN[SO.sub.2CF.sub.3].sub.2,
LiN[SO.sub.2CF.sub.2CF.sub.3].sub.2, LiC[SO.sub.2CF.sub.3].sub.3,
LiC[SO.sub.2CF.sub.2CF.sub.3].sub.2, LiB[OCOCF.sub.3].sub.4 and
LiB[OCOCF.sub.2CF.sub.3].sub.4.
10. The energy storage device according to claim 9, wherein said
electrolytic solution comprises at least one selected from the
group consisting of methyl acetate (MA), ethyl acetate (EA), methyl
propionate (MP) and ethyl propionate (ME).
11. The energy storage device according to claim 9, wherein said
electrolytic solution comprises at least one selected from the
group consisting of nonafluorobutyl methyl ether, nonafluorobutyl
ethyl ether and heptafluorocyclopentane.
12. The energy storage device according to claim 9, wherein said
electrolytic solution comprises at least one selected from the
group consisting of vinylene carbonate, ethylene sulfide, propane
sultone, diphenyl disulfide, methoxybenzene, methoxypyridine and
hexamethylcyclophosphazene.
13. A secondary battery which is a coin-shaped or cylindrical
battery comprising the energy device according to claim 1.
14. A redox capacitor comprising the energy device according to
claim 1.
15. An energy device module comprising a plurality of the energy
storage devices according to claim 1 connected to each other in
series, in parallel, or in series-parallel, and a control circuit
for controlling at least any one of the current and the voltage of
an electric circuit formed by said connection.
16. An electric vehicle comprising the energy storage device module
according to claim 15 mounted therein and an electric motor driven
by the power supplied by said module.
17. A hybrid vehicle comprising the energy storage device module
according to claim 15 mounted therein, and an electric motor driven
by the power supplied by said module and an internal combustion
engine.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a new energy storage device
for storing/releasing electric energy, a module thereof and an
electric vehicle using the module.
BACKGROUND ART
[0002] In these years, power supplies having higher input/output
power than hitherto available are required as power supplies for
electric vehicles, hybrid vehicles, electric tools or the like, and
additionally, power supplies capable of rapidly
charging/discharging and having high capacity are required.
Particularly, power supplies having small temperature dependence
and capable of maintaining input/output characteristics in a manner
better than ever, even at low temperatures such as -20.degree. C.
or -30.degree. C. are required.
[0003] Such requirements as described above have hitherto been
dealt with by making higher the performance of secondary batteries
being mainly faradic in reaction mechanism such as lithium
secondary batteries, nickel-hydrogen batteries, nickel-cadmium
batteries and lead batteries, and by using in combination electric
double layer capacitors being non4aradic in reaction mechanism and
satisfactory, as instantaneous input/output power supplies, in
input/output characteristics and in characteristics in low
temperature environments.
[0004] Also, Patent Document 1 discloses a lithium secondary
battery in which an activated carbon to be used as a material for
an electric double layer capacitor is mixed in the positive
electrode of the lithium secondary battery for the purpose of
attaining high energy density, high output density and improvement
of low temperature characteristics.
[0005] Patent Document 1: JP Patent Publication (Kokai) No.
2002-260634
SUMMARY OF THE INVENTION
[0006] Conventional lithium secondary batteries are poor in
charge/discharge characteristics for large current, and have a
problem that the input/output characteristics are markedly degraded
particularly under low-temperature conditions and the electric
double layer capacitors involved are low in energy density.
[0007] The present invention provides an energy storage device
excellent in input/output characteristics at low temperatures and
high in energy density, an module thereof and a vehicle using the
module.
[0008] The present invention provides an energy storage device
comprising: a positive electrode having a region where a reaction
accompanied by charge exchange occurs; a negative electrode having
a region where a reaction accompanied by charge exchange occurs; a
separator electrically separating the positive and negative
electrodes and allowing mobile ions to pass therethrough; an
electrolytic solution having an aprotic nonaqueous solvent
comprising the mobile ions; and a region in at least one of the
positive and negative electrodes where a charge adsorbing/desorbing
reaction occurs.
[0009] It is preferable that the regions where the reactions
accompanied by charge exchange occurs are formed in laminated
manner in current collectors and the regions where the charge
adsorbing/desorbing reactions occur are formed in a laminated
manner on the surfaces of the regions where the reactions
accompanied by charge exchange occurs. Alternatively, it is
preferable that the regions where the reaction accompanied by
charge exchange occurs and the regions where the charge
adsorbing/desorbing reaction occurs are formed on the surfaces of
the current collectors in an alternate manner.
[0010] In particular, the present invention provides an energy
storage device comprising a positive electrode to store/release
electric energy including a region I where a reaction accompanied
by charge exchange occurs and a region II where a charge
adsorbing/desorbing reaction occurs; a negative electrode to
store/release electric energy on the basis of a region I where a
reaction accompanied by charge exchange occurs, or on the basis of
a region I where a reaction accompanied by charge exchange occurs
and a region II where a charge adsorbing/desorbing reaction occurs;
a separator electrically separating the positive and negative
electrodes and allowing mobile ions to pass therethrough; and an
electrolytic solution comprising the mobile ions; wherein the
solvent constituting the electrolytic solution is an aprotic
nonaqueous solvent.
[0011] More specifically, it is preferable that in the energy
storage device according to the present invention, the positive
electrode layers formed as the positive electrode on both sides of
a highly conductive current collector are constituted with the
region I belonging to a reaction, to occur through charge exchange,
occuluding/releasing lithium as a compound on the basis of the
reaction to occur through charge exchange and the region II
belonging to a charge adsorbing/desorbing reaction to store
electricity through adsorption/desorption based on the electric
potential of the anion. The formation of these two regions is
compatible with any forms through forming predetermined regions in
the states such as a state of being partially mixed with each
other, a state of being formed in a manner partitioned into plane
sections, and a state of being formed in a manner laminated on the
surface of the current collector; no particular constraint is
imposed on the formation state, but formation in a laminated manner
is preferable. The formation in a laminated manner is such that the
region I is formed on the current collector side, and the region II
is formed on the surface of the region I thus formed, and the
region II of the positive electrode is abutted on the region I or
the region II of the negative electrode through the intermediary of
a separator.
[0012] Examples of the material capable of forming the region I
where the reaction accompanied by charge exchange occurs include
LiNi.sub.xMn.sub.yCo.sub.zO.sub.2 (with the proviso that x+y+z=1),
a composite oxide comprising Li and one or more transition metals
such as Co, Ni, Mn and Fe, and an olivine-structured phosphate
compound represented by LiMePO.sub.4 (Me being Fe, Co or Cr). More
specifically, LiNi.sub.1/3Mn.sub.1/3Co.sub.1/3O.sub.2,
LiNi0.4Mn.sub.0.3Co.sub.0.2O.sub.2, LiFePO.sub.4, LiCoPO.sub.4,
LiCrPO.sub.4 and the like can be used. These compounds are low in
electric conductance, and for the purpose of compensating this low
conductance, amorphous carbon materials such as graphite carbon
powder and acetylene black can also be used as conducting aids in a
manner mixed with these compounds.
[0013] As the materials to be used in combination for the reaction
accompanied by charge exchange, organic conducting materials doped
with alkali metals, alkali earth metals, onium ions, phosphonium
ions or acetylcholin can be used. Examples of the usable organic
conductors include polypyrrole, polythiophene, polyacetylene,
TTF(tetrathiafulvalene)-TCNQ(tetracyanoquinodimethane) complex,
polyisonaphthothiophene, polyparaphenylene,
polyparaphenylenevinylene and polythiophenevinylene.
[0014] As the material applicable to the region II where the charge
adsorbing/desorbing reaction occurs, activated carbon and carbon
nanotube can be used. Preferable is an activated carbon suitably
having a particle size of 1 to 100 .mu.m, a specific surface area
of 1000 to 3000 m.sup.2/g, pores called micropores of 0.002 .mu.m
or less in diameter, pores called mesopores of 0.002 to 0.05 .mu.m
in diameter and pores called macropores of 0.05 .mu.m or more in
diameter.
[0015] The positive electrode composed of the current collector and
the positive electrode layers is made to face the separator having
a large number of pores to hold the electrolytic solution and to
allow mobile ions to permeate therethrough, and is further made to
face the negative electrode through the intermediary of the
separator.
[0016] The negative electrode is composed of a highly conductive
metal current collector and negative electrode layers formed on
both sides of the current collector. The negative electrode is
constituted with the region I belonging to the reaction to occur
through charge exchange, or with the region I belonging to the
reaction to occur through charge exchange and the region II
belonging to the charge adsorbing/desorbing reaction. Examples of
materials usable as the materials belonging to the charge
donating/accepting reaction include lithium metal, a lithium alloy,
silicon, silicon oxides, tin, tin oxides, and composite materials
composed of a carbonaceous material and one or more of lithium
metal, a lithium alloy, silicon, silicon oxides, tin and tin
oxides. Examples of materials usable as the materials belonging to
the charge adsorbing/desorbing reaction include activated carbon
and carbon nanotube. Alkali- or steam-treated products of expanded
graphite and amorphous carbon capable of allowing both of these
reactions to occur in a concerted manner can also be used.
[0017] These electrodes each are prepared by being applied as a
paste containing a binder to be formed on both sides of the current
collector, then dried, pressed and heated. As the binder,
polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl alcohol
derivatives, styrenebutadiene rubber and the like can be used.
[0018] To the positive and negative electrodes prepared as
described above, metal foil tabs made of nickel or the like are
welded, the positive and negative electrodes being connected to the
battery can and the battery lid through these tabs. The connection
of the positive and negative electrodes to the battery can or the
battery lid is optional. It is to be noted that when the battery
can is made of aluminum, the positive electrode is preferably
connected to the battery can. A packing is an insulator serving to
make the polarities of the battery can and the battery lid
independent of each other, and also has a function to maintain the
internal airtightness. As the packing, molded articles made of
rubber or fluororubber can be used. For the insulators to protect
the connection between the battery tabs and the battery can and the
connection between the battery tabs and the battery lid, polyimide
film or the like can be used. The battery is fabricated in such a
way that the electrolytic solution is injected and then the
positive electrode lid and the battery can are crimped to each
other to seal the battery.
[0019] For the electrolytic solution, the nonaqueous solvents
represented by formulas (1) to (20) can be used as admixtures.
[0020] Examples of the compounds represented by formula (1) include
ethylene carbonate, propylene carbonate, butylene carbonate,
trifluoroethylene carbonate, chloroethylene carbonate,
fluoroethylene carbonate, difluoroethylene carbonate and
vinylethylene carbonate.
[0021] Examples of the compounds represented by formula (2) include
dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate,
methyl propyl carbonate, ethyl propyl carbonate, dipropyl
carbonate, trifluoromethyl methyl carbonate and trifluoroethyl
methyl carbonate.
[0022] Examples of the compounds represented by formula (3) include
methyl formate, ethyl formate, propyl formate, methyl acetate,
ethyl acetate, propyl acetate, methyl propionate, ethyl propionate
and propyl propionate.
[0023] Examples of the compounds represented by formula (4) include
.gamma.-butylolactone, .alpha.-bromo-.gamma.-butylolactone,
.alpha.-methyl-.gamma.-butylolactone,
.alpha.-fluoro-.gamma.-butylolactone,
.alpha.-chloro-.gamma.-butylolactone,
.alpha.-methoxy-.gamma.-butylolactone,
.alpha.-acetyl-.gamma.-butylolactone,
.beta.-fluoro-.gamma.-butylolactone and
.gamma.-fluoro-.gamma.-butylolactone.
[0024] Examples of the compounds represented by formula (5) include
1,3-dioxolane, 2-methyl-1,3-dioxolane, 2,2-dimethyl-1,3-dioxolane,
4-methyl-1,3-dioxolane and 4,4-dimethyl-1,3-dioxolane.
[0025] Examples of the compounds represented by formula (6) include
monoglyme, diglyme and triglyme, and examples of the compounds
represented by formula (7) include tetrahydrofuran,
1-ethyl-tetrahydrofuran, 2-methyl-tetrahydrofuran, and
2,3-dimethyl-tetrahydrofuran.
[0026] Examples of the compounds represented by formula (8) include
methyl nonafluorobutyl ether, ethyl nonafluorobutyl ether, dimethyl
ether and diethyl ether, and examples of the compounds represented
by formula (9) include 1,1,2,2,3,3,4-heptafluorocyclopentane,
cyclopentane and methoxycyclopentane.
[0027] Examples of the compounds represented by formula (10)
include trifluoromethylheptane, butyl iodide and
pentafluoroethylheptane, and examples of the compounds represented
by formula (11) include vinylene carbonate, methylvinylene
carbonate, dimethyl vinylene carbonate and ethylvinylene
carbonate.
[0028] Examples of the compounds represented by formula (12)
include biphenyl, terphenyl and p-dimethylbiphenyl, and examples of
the compounds represented by formula (13) include ethylene sulfide,
methylethylene sulfide, dimethylethylene sulfide and
ethylmethylethylene sulfide.
[0029] Examples of the compounds represented by formula (14)
include propane sultone, 3-methyl-propane sultone, 4-methyl-propane
sultone, 5-methyl-propane sultone, 3-fluoro-propane sultone and
4-fluoro-propane sultone, and examples of the compounds represented
by formula (15) include diphenyl disulfide, p-dimethyl disulfide,
bisdiethylthiocarbomyl disulfide and diallyl disulfide.
[0030] Examples of the compounds represented by formula (16)
include methoxy benzene, dimethoxy benzenes, fluorobenzene,
difluorobenzenes and methylmethoxybenzenes, and examples of the
compounds represented by formula (17) include o-methoxypyridine,
m-methoxypyridine, p-methoxypyridine, o-ethoxypyridine,
m-ethoxypyridine and p-ethoxypyridine.
[0031] Examples of the compounds represented by formula (18)
include hexamethoxytriphosphazene, hexaethoxytriphosphazene and
hexapropoxytriphosphazene, and examples of the compounds
represented by formula (19) include hexamethoxycyclotriphosphazene,
hexaethoxycyclotriphosphazene and
hexapropoxycyclotriphosphazene.
[0032] Examples of the compounds represented by formula (20)
include trimethyl phosphate, triethyl phosphate and tripropyl
phosphate.
[0033] As the electrolyte salts, the following salts can be used
each alone or as admixtures of two or more thereof: LiPF.sub.6,
LiAsF.sub.6, LiBF.sub.4, LiSO.sub.2CF.sub.3,
LiN[SO.sub.2CF.sub.3].sub.2, LiN[SO.sub.2CF.sub.2CF.sub.3].sub.2,
LiC[SO.sub.2CF.sub.3].sub.3, LiC[SO.sub.2CF.sub.2CF.sub.3].sub.2,
LiB[OCOCF.sub.3].sub.4, LiB[OCOCF.sub.2CF.sub.3].sub.4, LiI, LiBr,
LiCl, NaPF.sub.6, NaAsF.sub.6, NaBF.sub.4, NaSO.sub.2CF.sub.3,
NaN[SO.sub.2CF.sub.3].sub.2, NaN[SO.sub.2CF.sub.2CF.sub.3].sub.2,
NaC[SO.sub.2CF.sub.3].sub.3, NaC[SO.sub.2CF.sub.2CF.sub.3].sub.2,
NaB[OCOCF.sub.3].sub.4, NaB[OCOCF.sub.2CF.sub.3].sub.4, NaI, NaBr
and NaCl.
[0034] By mixing an appropriate amount of a polymer resin in an
electrolytic solution, the electrolytic solution can be converted
into a gelled electrolyte to be used in place of the electrolytic
solution. Examples of the polymers to be mixed to prepare the
gelled electrolyte include polyethylene oxide (PEO),
polymethacrylate (PMMA), polyacrylonitrile (PAN), polyvinylidene
fluoride (PVDF) and polyvinylidene fluoride-hexafluoropropylene
copolymer (PVDF-HFP).
[0035] According to the present invention, a plurality of energy
storage devices are connected to form an energy storage device
module in which the plurality of energy storage devices are
connected (e.g. in series) in compliance with the desired voltages.
The voltage detecting units for detecting these individual voltages
and the control circuits for controlling the charging and
discharging currents flowing in the individual energy storage
devices are installed, and the units for sending commands to these
units are also installed. The communications between these units
are set to be conducted by means of electric signals. At the time
of charging, when the voltages of the individual energy storage
devices, detected by the voltage detecting units are lower than the
preset charging voltages, electric currents are made to flow into
the energy storage devices to charge the devices. For the energy
storage devices having reached the preset charging voltages, the
electric signals from the units for sending commands make the
charging currents not flow into the energy storage devices so as to
prevent the overcharge thereof.
[0036] On the other hand, at the time of discharging, similarly the
voltages of the individual energy storage devices are detected by
the units for detecting voltage, and when the energy storage
devices reach the predetermined discharging voltages, the
discharging currents are made not to flow. As for the precision of
the voltage detection, the voltage resolution is preferably 0.1 V
or less, and more preferably 0.02 V or less. The energy storage
device module can be actualized by detecting the voltages of the
individual energy storage devices in satisfactory precisions as
described above, and by controlling the energy storage devices so
as to be operated without undergoing overcharging or
overdischarging.
[0037] According to the present invention, there can be obtained an
energy storage device being excellent in the input/output
characteristics at low temperatures and having a high energy
density, a module thereof, and an electric vehicle using the module
and a hybrid vehicle using the module.
BRIEF DESCRIPTION OF THE DRAWINGS
[0038] FIG. 1 is a partial sectional view of a cylindrical lithium
secondary battery as an energy storage device according to the
present invention;
[0039] FIG. 2 is a graph showing the relationship between the
current and the voltage obtained for the lithium secondary battery
according to the present invention;
[0040] FIG. 3 is a graph showing the relationship between the
output power and the battery voltage showing the output
characteristics of the lithium secondary battery according to the
present invention at -30.degree. C.;
[0041] FIG. 4 is an oblique perspective view showing an energy
storage device module according to the present invention; and
[0042] FIG. 5 is an underside front view of a hybrid electric
vehicle using the energy storage device module according to the
present invention.
[0043] 1 . . . current collector (positive electrode)
[0044] 2 . . . positive electrode layer
[0045] 3 . . . current collector (negative electrode)
[0046] 4 . . . negative electrode layers
[0047] 5 . . . separator
[0048] 6 . . . negative electrode tab
[0049] 7 . . . positive electrode tab
[0050] 8 . . . positive electrode insulator
[0051] 9 . . . negative electrode insulator
[0052] 10 . . . battery can
[0053] 11 . . . battery lid
[0054] 12 . . . gasket
[0055] 71 . . . energy storage device
[0056] 72 . . . container
[0057] 73 . . . bus bar
[0058] 74 . . . positive electrode terminal
[0059] 75 . . . negative electrode terminal
[0060] 76 . . . module positive electrode terminal
[0061] 77 . . . control circuit
[0062] 78 . . . vent hole
[0063] 79 . . . module negative electrode terminal
[0064] 81 . . . energy storage device module
[0065] 82 . . . module control circuit
[0066] 83 . . . drive motor
[0067] 84 . . . engine
[0068] 85 . . . inverter
[0069] 86 . . . motive power control circuit
[0070] 87 . . . drive shaft
[0071] 88 . . . differential gear
[0072] 89 . . . drive wheel
[0073] 810 . . . clutch
[0074] 811 . . . clutch gear
[0075] 812 . . . speed monitor
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0076] Specific description will be made below with reference to
further detailed examples of an energy storage device of the
present invention, but the present invention is not limited to the
examples to be described below.
EXAMPLE 1
[0077] FIG. 1 is a partial sectional view of a cylindrical lithium
secondary battery as an energy storage device showing an embodiment
of the present invention. Positive electrode layers 2 formed as a
positive electrode on both sides of a highly conductive current
collector 1 were constituted with a region I belonging to a
reaction, to occur through charge exchange, occluding/releasing
lithium as a compound on the basis of a reaction to occur through
charge exchange, and a region II belonging to a charge
adsorbing/desorbing reaction to store electricity through
adsorption/desorption based on the electric potential of the anion.
The positive electrode composed of the current collector 1 and the
positive electrode layers 2 was made to face a separator 5 having a
large number of pores to hold an electrolytic solution and to allow
mobile ions to permeate therethrough, and was further made to face
a negative electrode through the intermediary of the separator
5.
[0078] A positive electrode slurry was prepared as follows: as an
active material in the region I where the reaction accompanied by
charge exchange occurs in the positive electrode,
LiNi.sub.1/3Mn.sub.1/3Co.sub.1/2O.sub.2 was used; as a conducting
aid, a 4:1 by weight mixture of a graphite carbon having an average
particle size of 3 .mu.m and a specific surface area of 13
m.sup.2/g and a carbon black having an average particle size of
0.04 .mu.m and a specific surface area of 40 m.sup.2/g was used; as
a binder, a 8 wt % solution of polyvinylidene fluoride beforehand
dissolved in NMP was used; the positive electrode material, the
conducting aid and the polyvinylidene fluoride solution were mixed
together so as for the ratio between the positive electrode active
material, the conducting aid and polyvinylidene fluoride to be
85:10:5; and the mixture was fully kneaded to yield the positive
electrode slurry. The both sides of the positive electrode current
collector 1 formed of 20 .mu.m thick aluminum foil were coated with
the positive slurry and dried. Then, the current collector 1 was
pressed with a roll press and further dried to yield an electrode
as a positive electrode material having the region I where the
reaction accompanied by charge exchange occurs.
[0079] Additionally, another slurry was prepared as follows: a 8:1
by weight carbon mixture of an activated carbon having a specific
surface area of 2000 m.sup.2/g and a carbon black having an average
particle size of 0.04 .mu.m and a specific surface area of 40
m.sup.2/g was prepared; as a binder, a 8 wt % solution of
polyvinylidene fluoride beforehand dissolved in N-methylpyrrolidone
was used; the carbon mixture and the binder solution were mixed
together so as for the ratio between the activated carbon, the
carbon black and polyvinylidene fluoride to be 80:10:10; and the
mixture was fully kneaded to yield the slurry. The surface of the
above electrode as a positive electrode material was coated with
this slurry to form the region II where the charge
adsorbing/desorbing reaction occurs, dried and pressed with a press
roll to prepare the positive electrode. A positive electrode tab 7
made of nickel foil as a terminal was supersonically welded to one
end of the electrode to complete the positive electrode.
[0080] A negative electrode comprised a highly conductive metal
current collector 3 and negative electrode layers 4 formed on both
sides thereof. The negative electrode layers 4 each were
constituted with the region I belonging to the reaction to occur
through charge exchange, or the region I belonging to the reaction
to occur through charge exchange and the region II belonging to the
charge adsorbing/desorbing reaction.
[0081] As a negative electrode active material, a negative
electrode slurry was prepared as follows: a 95:5 by weight carbon
mixture was prepared by mechanically mixing an amorphous carbon
having an average particle size of 9 .mu.m with a carbon black
having an average particle size of 0.04 .mu.m and a specific
surface area of 40 m.sup.2/g; as a binder, a 8 wt % solution of
polyvinylidene fluoride beforehand dissolved in N-methylpyrrolidone
was used; the carbon material mixture mixed in advance composed of
the amorphous carbon and the carbon black and the binder solution
were fully kneaded so as for the ratio between the carbon material
mixture and polyvinylidene fluoride to be 90:10 to yield the
negative electrode slurry. The both sides of a negative electrode
current collector 3 made of a 10 .mu.m thick copper foil were
coated with the slurry and dried to form the region I. The member
thus formed was pressed with a roll press, and a negative electrode
tab 6 made of nickel foil was supersonically welded to an uncoated
end of the current collector to prepare the negative electrode. As
for the formation of the region II, the region II was able to be
formed in the same manner as in the positive electrode layer 2.
[0082] An electrode assembly was prepared by winding the positive
and negative electrodes prepared as described above in a manner
sandwiching therebetween a 30 .mu.m thick finely porous separator 5
having a three-layered structure of PE/PP/PE
(polyethylene/polypropylene/polyethylene). The electrode assembly
was put in a battery can 10, and then a negative electrode tab 6
was spot welded to the bottom of the battery can 10 to be connected
thereto. An electrolytic solution was filled in the battery can 10
from the upper portion thereof, then the battery can 10 and the
battery lid 11 were crimped to each other to seal the battery, and
thus a lithium secondary battery was fabricated.
[0083] The positive electrode tab 7 and the negative electrode tab
6, each made of a metal foil of nickel or the like, were welded to
the positive and negative electrodes, respectively, and the
positive and negative electrodes were connected to the battery can
10 and the battery lid 11 through these tabs. The connection of the
positive and negative electrodes to the battery can 10 or the
battery lid 11 is optional. It is to be noted that when the battery
can 10 is made of aluminum, the positive electrode is preferably
connected to the battery can 10. A packing 12 is an insulator
serving to make the polarities of the battery can 10 and the
battery lid 11 independent of each other, and also has a function
to maintain the internal airtightness. As the packing 12, molded
articles made of rubber or fluororubber can be used. For the
positive electrode insulator 8 and the negative electrode insulator
9 to respectively protect the connection between the positive
electrode tab 7 and the battery can 10 or the battery lid 11 and
the connection between the negative electrode tab 6 and the battery
can 10 or the battery lid 11, polyimide film or the like can be
used.
[0084] In present Example 1, as the electrolytic solution, there
was used a solution in which the solvent was a 1:2 (EC:EMC) by
volume solvent mixture of ethylene carbonate (EC) and ethyl methyl
carbonate (EMC), LiPF.sub.6 was dissolved in the mixed solvent in a
concentration of 1 mol/dm.sup.3 (M), and vinylene carbonate (VC)
was further added in a content of 2 wt %.
[0085] The lithium secondary battery was charged at a constant
current of 200 mA until the battery voltage reached 4.1 V, and then
the battery was charged at the constant voltage of 4.1 V until the
current value reached 10 mA; after an intermission of 30 min, the
battery was discharged at a constant current of 200 mA until the
battery voltage reached 2.7 V. This charging-discharging cycle was
repeated three times, and the discharge capacity of the third cycle
was recorded. The discharge capacity of the lithium secondary
battery was 210 mAh.
[0086] FIG. 2 is a graph showing the relationship between the
current and the voltage obtained for the lithium secondary battery.
From FIG. 2, the direct-current resistance (DCR) concerned was
derived, and the maximum available output power at a predetermined
voltage was obtained. More specifically, in the derivation of the
output power, at the beginning the battery was charged until a
predetermined voltage V1 was reached, and then battery was
discharged for 20 sec at a current of 200 mA, 1 A, 2 A, 5 A and 8
A, and thus the values at a discharging time of 1 sec were
measured. The DCR value at the voltage of V1 was obtained from the
slope of the line of FIG. 2, the maximum allowable voltage was set
at 2.5 V, the maximum available current value Imax was determined
as the current value at 2.5 V on this line, and thus the output
power P.sub.max was derived on the basis of the following formula:
P.sub.max=(I.sub.max).times.(V.sub.o) wherein V.sub.o is the
extrapolated intersection point of the I-V plot and corresponds to
the open circuit voltage.
COMPARATAIVE EXAMPLE 1
[0087] In Comparative Example 1, as the positive electrode, only
the same region I where the reaction accompanied by charge exchange
occurs as in Example 1 was formed; for the negative electrode, the
same electrode as in Example 1 was prepared; the same electrolytic
solution as in Example 1 was used; and thus, the lithium secondary
battery of Comparative Example 1 corresponding to a conventional
lithium secondary battery was fabricated.
[0088] FIG. 3 is a graph showing the relationship between the
output power and the battery voltage showing the output
characteristics of the lithium secondary battery at -30.degree. C.
As shown in FIG. 3, the output power at 3.65 V in Example 1 was
4.89 W, but the output power at 3.65 V in Comparative Example 1 was
of the order of 3.93 W. The discharge capacity of the lithium
secondary battery of Comparative Example 1 was 205 mAh.
[0089] As described above, the output power at -30.degree. C. of
Example 1 was verified to be improved even by 24% as compared to
that of Comparative Example 1.
EXAMPLE 2
[0090] The positive electrode was prepared as follows: as the
active material in the region I where the reaction accompanied by
charge exchange occurs in the positive electrode layer 2,
LiNi.sub.1/3Mn.sub.1/3Co.sub.1/3O.sub.2 was used; as the conducting
aid, a 4:1 by weight mixture of a graphite carbon having an average
particle size of 3 .mu.m and a specific surface area of 13
m.sup.2/g and a carbon black having an average particle size of
0.04 .mu.m and a specific surface area of 40 m.sup.2/g was used; as
a material forming the region II where the charge
adsorbing/desorbing reaction occurs, an activated carbon having a
relatively higher specific surface area of 2000 m.sup.2/g was used;
a positive electrode material paste was prepared with NMP as the
solvent so as for the ratio between
LiNi.sub.1/3Mn.sub.1/3Co1/3O.sub.2, the conducting aid, the
activated carbon and the binder PVDF to be 77:5:10:8 in the solid
content ratio by weight; and the both sides of a current collector
1 were coated with the paste, dried and pressed to prepare the
positive electrode. The same negative electrode and the same
electrolytic solution as in Example 1 were used, and thus the
energy storage device of Example 2 was fabricated. The specific
area of the activated carbon is preferably 2000 to 5000 m.sup.2/g.
The discharge capacity of this device was 197 mAh. The output power
thereof at -30.degree. C. and at 3.65 V was 4.76 W, to be higher
even by 21% than in Comparative Example 1. Here, the positive
electrode was formed with the region I and the region II mixed with
each other, but the positive electrode may also be obtained by
forming the region I and the region II alternately in predetermined
areas on the surface of the positive electrode current collector
1.
EXAMPLE 3
[0091] The energy storage device of Example 3 was fabricated with
the same electrode configuration as in Example 1 and with an
electrolytic solution prepared by dissolving LiPF.sub.6 in a
concentration of 1 M in a 3:3:1 by volume solvent mixture of EC,
EMC and methyl acetate (MA) and by adding VC in a content of 2 wt
%. The discharge capacity was 225 mAh, and the output power at
-30.degree. C. and at 3.65 V was 4.97 W, to be higher even by 26%
than in Comparative Example 1.
EXAMPE 4
[0092] The energy storage device of Example 4 was fabricated with
the same electrode configuration as in Example 1 and with an
electrolytic solution prepared by dissolving LiPF.sub.6 in a
concentration of 1 M in a 3:3:1 by volume solvent mixture of EC,
EMC and methyl acetate (MA) and by adding VC in a content of 2 wt %
and by further adding LiB[OCOCF.sub.3].sub.4 in a content of 0.2 wt
%. The discharge capacity was 222 mAh, and the output power at
-30.degree. C. and at 3.65 V was 5.15 W, to be higher even by 31%
than in Comparative Example 1.
EXAMPLE 5
[0093] The energy storage device of Example 5 was fabricated with
the same electrode configuration as in Example 1 and with an
electrolytic solution prepared by dissolving LiPF.sub.6 in a
concentration of 1 M in a 3:3:3:1 by volume solvent mixture of EC,
DMC, EMC and methyl acetate (MA) and by adding VC in a content of 2
wt %. The discharge capacity was 230 mAh, and the output power at
-30.degree. C. and at 3.65 V was 5.05 W, to be higher even by 28%
than in Comparative Example 1.
EXAMPLE 6
[0094] The energy storage device of Example 6 was fabricated with
the same electrode configuration as in Example 1 and with an
electrolytic solution prepared by dissolving LiPF.sub.6 in a
concentration of 1 M in a 3:3:3:1 by volume solvent mixture of EC,
.gamma.-butyrolactone (GBL), EMC and methyl acetate (MA) and by
adding VC in a content of 2 wt %. The discharge capacity was 215
mAh, and the output power at -30.degree. C. and at 3.65 V was 5.21
W, to be higher even by 32% than in Comparative Example 1.
EXAMPLE 7
[0095] The energy storage device of Example 7 was fabricated with
the same electrode configuration as in Example 1 and with an
electrolytic solution prepared by dissolving LiPF.sub.6 in a
concentration of 1 M in a 3:2:3:1:1 by volume solvent mixture of
EC, .gamma.-butyrolactone (GBL), EMC, methyl acetate (MA) and
methyl nonafluorobutyl ether (MFE) and by adding VC in a content of
2 wt %. The discharge capacity of ED7 was 224 mAh, and the output
power at -30.degree. C. and at 3.65 V was 5.21 W, to be higher even
by 33% than in Comparative Example 1.
EXAMPLE 8
[0096] The energy storage device ED8 of Example 8 was fabricated
with the same electrode configuration as in Example 1 and with an
electrolytic solution prepared by dissolving LiPF.sub.6 in a
concentration of 1 M in a 3:5:1:1 by volume solvent mixture of EC,
EMC, methyl acetate (MA) and 1,1,2,2,3,3,4-heptafluorocyclopentane
(HFCP) and by adding VC in a content of 2 wt %. The discharge
capacity was 214 mAh, and the output power at -30.degree. C. and at
3.65 V was 5.21 W, to be higher even by 32% than in Comparative
Example 1.
EXAMPLE 9
[0097] The energy storage device of Example 9 was fabricated with
the same electrode configuration as in Example 1 and with an
electrolytic solution prepared by dissolving LiPF.sub.6 in a
concentration of 1 M in a 3:5:1:1 by volume solvent mixture of EC,
EMC, methyl acetate (MA) and 1,1,2,2,3,3,4-heptafluorocyclopentane
(HFCP) and by adding VC in a content of 2 wt %. The discharge
capacity was 214 mAh, and the output power at -30.degree. C. and at
3.65 V was 5.21 W, to be higher even by 32% than in Comparative
Example 1.
EXAMPLE 10
[0098] The energy storage device of Example 10 was fabricated with
the same electrode configuration as in Example 1 and with an
electrolytic solution prepared by dissolving LiPF.sub.6 in a
concentration of 1 M in a 3:3:3:1 by volume solvent mixture of EC,
DMC, EMC and ethyl acetate (EA) and by adding VC in a content of 2
wt %. The discharge capacity was 222 mAh, and the output power at
-30.degree. C. and at 3.65 V was 4.98 W, to be higher even by 26%
than in Comparative Example 1.
EXAMPLE 11
[0099] The energy storage device of Example 11 was fabricated with
the same electrode configuration as in Example 1 and with an
electrolytic solution prepared by dissolving LiPF.sub.6 in a
concentration of 1 M in a 3:3:3:1 by volume solvent mixture of EC,
DMC, EMC and methyl propionate (PM) and by adding VC in a content
of 2 wt %. The discharge capacity was 226 mAh, and the output power
at -30.degree. C. and at 3.65 V was 5.11 W, to be higher even by
30% than in Comparative Example 1.
EXAMPLE 12
[0100] The energy storage device of Example 12 was fabricated with
the same electrode configuration as in Example 1 and with an
electrolytic solution prepared by dissolving LiPF.sub.6 in a
concentration of 1 M in a 3:3:3:1 by volume solvent mixture of EC,
DMC, EMC and MA and by adding vinylethylene carbonate (VEC) in a
content of 2 wt %. The discharge capacity was 228 mAh, and the
output power at -30.degree. C. and at 3.65 V was 5.09 W, to be
higher even by 29% than in Comparative Example 1.
EXAMPLE 13
[0101] The energy storage device of Example 13 was fabricated with
the same electrode configuration as in Example 1 and with an
electrolytic solution prepared by dissolving LiPF.sub.6 in a
concentration of 1 M in a 3:3:3:1 by volume solvent mixture of EC,
DMC, EMC and MA and by adding VC in a content of 2 wt % and further
adding anisole (AN) in a content of 3 wt %. The discharge capacity
was 221 mAh, and the output power at -30.degree. C. and at 3.65 V
was 5.05 W, to be higher even by 28% than in Comparative Example
1.
EXAMPLE 14
[0102] The energy storage device of Example 14 was fabricated with
the same electrode configuration as in Example 1 and with an
electrolytic solution prepared by dissolving LiPF.sub.6 in a
concentration of 1 M in a 3:3:3:1 by volume solvent mixture of EC,
DMC, EMC and MA and by adding VC in a content of 2 wt % and further
adding 2-fuoroanisole (FAN) in a content of 3 wt %. The discharge
capacity was 218 mAh, and the output power at -30.degree. C. and at
3.65 V was 5.02 W, to be higher even by 28% than in Comparative
Example 1.
EXAMPLE 15
[0103] The energy storage device of Example 15 was fabricated with
the same electrode configuration as in Example 1 and with an
electrolytic solution prepared by dissolving LiPF.sub.6 in a
concentration of 1 M in a 3:3:3:1 by volume solvent mixture of EC,
DMC, EMC and MA and by adding VC in a content of 2 wt % and further
adding terphenyl in a content of 3 wt %. The discharge capacity was
211 mAh, and the output power at -30.degree. C. and at 3.65 V was
4.97 W, to be higher even by 26% than in Comparative Example 1.
EXAMPLE 16
[0104] The energy storage device of Example 16 was fabricated with
the same electrode configuration as in Example 1 and with an
electrolytic solution prepared by dissolving LiPF.sub.6 in a
concentration of 1 M in a 3:3:3:1 by volume solvent mixture of EC,
DMC, EMC and GBL and by adding VC in a content of 2 wt %. The
discharge capacity was 211 mAh, and the output power at -30.degree.
C. and at 3.65 V was 5.01 W, to be higher even by 27% than in
Comparative Example 1.
EXAMPLE 17
[0105] The energy storage device of Example 17 was fabricated with
the same electrode configuration as in Example 1 and with an
electrolytic solution prepared by dissolving LiPF.sub.6 in a
concentration of 1 M in a 3:3:3:1 by volume solvent mixture of EC,
DMC, EMC and ethylene sulfite (ES) and by adding VC in a content of
2 wt %. The discharge capacity was 226 mAh, and the output power at
-30.degree. C. and at 3.65 V was 5.07 W, to be higher even by 29%
than in Comparative Example 1.
EXAMPLE 18
[0106] The energy storage device of Example 18 was fabricated with
the same electrode configuration as in Example 1 and with an
electrolytic solution prepared by dissolving LiPF.sub.6 in a
concentration of 1 M in a 3:3:3:1 by volume solvent mixture of EC,
DMC, EMC and MA and by adding VC in a content of 2 wt % and further
adding ES in a content of 2 wt %. The discharge capacity was 231
mAh, and the output power at -30.degree. C. and at 3.65 V was 5.02
W, to be higher even by 27% than in Comparative Example 1.
EXAMPLE 19
[0107] The energy storage device of Example 19 was fabricated with
the same electrode configuration as in Example 1 and with an
electrolytic solution prepared by dissolving LiPF.sub.6 in a
concentration of 1 M in a 3:3:3:1 by volume solvent mixture of EC,
DMC, EMC and MA and by adding VC in a content of 2 wt % and further
adding propane sultone (PS) in a content of 2 wt %. The discharge
capacity was 235 mAh, and the output power at -30.degree. C. and at
3.65 V was 5.09 W, to be higher even by 29% than in Comparative
Example 1.
EXAMPLE 20
[0108] The energy storage device of Example 20 was fabricated with
the same electrode configuration as in Example 1 and with an
electrolytic solution prepared by dissolving LiPF.sub.6 in a
concentration of 1 M in a 3:3:3:1 by volume solvent mixture of EC,
DMC, EMC and MA and by adding VC in a content of 2 wt % and propane
sultone (PS) in a content of 2 wt %, and further adding diphenyl
disulfide (DDS) in a content of 2 wt %. The discharge capacity was
223 mAh, and the output power at -30.degree. C. and at 3.65 V was
5.02 W, to be higher even by 27% than in Comparative Example 1.
EXAMPLE 21
[0109] The energy storage device of Example 21 was fabricated with
the same electrode configuration as in Example 1 and with an
electrolytic solution prepared by dissolving LiPF.sub.6 in a
concentration of 1 M in a 3:3:3:1 by volume solvent mixture of EC,
DMC, EMC and MA and by adding VC in a content of 2 wt % and propane
sultone (PS) in a content of 2 wt %, and further adding pyridine
(PN) in a content of 2 wt %. The discharge capacity was 239 mAh,
and the output power at -30.degree. C. and at 3.65 V was 5.12 W, to
be higher even by 30% than in Comparative Example 1.
EXAMPLE 22
[0110] The energy storage device of Example 22 was fabricated with
the same electrode configuration as in Example 1 and with an
electrolytic solution prepared by dissolving LiPF.sub.6 in a
concentration of 1 M in a 3:3:3:1 by volume solvent mixture of EC,
DMC, EMC and MA and by adding VC in a content of 2 wt % and propane
sultone (PS) in a content of 2 wt %, and further adding
2-methoxy-pyridine (MePN) in a content of 2 wt %. The discharge
capacity was 236 mAh, and the output power at -30.degree. C. and at
3.65 V was 5.13 W, to be higher even by 30% than in Comparative
Example 1.
EXAMPLE 23
[0111] The energy storage device of Example 23 was fabricated with
the same electrode configuration as in Example 1 and with an
electrolytic solution prepared by dissolving LiPF.sub.6 in a
concentration of 1 M in a 3:3:3:1 by volume solvent mixture of EC,
DMC, EMC and MA and by adding VC in a content of 2 wt % and further
adding chain hexamethoxytriphosphazene (HFTH) in a content of 2 wt
%. The discharge capacity was 236 mAh, and the output power at
-30.degree. C. and at 3.65 V was 5.04 W, to be higher even by 28%
than in Comparative Example 1.
EXAMPLE 24
[0112] The energy storage device of Example 24 was fabricated with
the same electrode configuration as in Example 1 and with an
electrolytic solution prepared by dissolving LiPF.sub.6 in a
concentration of 1 M in a 3:3:3:1 by volume solvent mixture of EC,
DMC, EMC and MA and by adding VC in a content of 2 wt % and further
adding cyclic hexamethoxytriphosphazene (cHFTH) in a content of 2
wt %. The discharge capacity was 231 mAh, and the output power at
-30.degree. C. and at 3.65 V was 5.02 W, to be higher even by 27%
than in Comparative Example 1.
EXAMPLE 25
[0113] The energy storage device of Example 25 was fabricated with
the same electrode configuration as in Example 1 and with an
electrolytic solution prepared by dissolving LiPF.sub.6 in a
concentration of 1 M in a 3:3:2:1:1 by volume solvent mixture of
EC, DMC, EMC, MA and trimethyl phosphate (TMP) and by adding VC in
a content of 2 wt %. The discharge capacity was 227 mAh, and the
output power at -30.degree. C. and at 3.65 V was 4.96 W, to be
higher even by 26% than in Comparative Example 1.
EXAMPLE 26
[0114] FIG. 4 is an oblique perspective view showing an energy
storage device module fabricated with a plurality of the energy
storage devices according to the present invention. The energy
storage devices 71 were the ones fabricated in Example 1; 24 of the
energy storage devices 71 were connected in series and put in a
rectangular box-shaped resin container 72. Copper plates 73 of 2 mm
in thickness were used to connect the individual energy storage
devices 91 to each other; each of the cooper plates 73 was screwed
to the positive electrode terminal 74 of one of the energy storage
devices 71 and to the negative electrode terminal 75 of another one
of the energy storage devices 71 so as to connect these energy
storage devices. The charge/discharge current of the module is
input/output through cables 76. Each of the energy storage devices
71 is connected to a control circuit 77 through a signal wire, so
that the voltage and temperature of each of the energy storage
devices 71 can be monitored in the course of charging/discharging.
The module is provided with a vent hole 78 for cooling. In this
module, the maximum terminal voltage between the terminal 76 and
the terminal 79 was 98 V. This module generated an output power of
115 W at -30.degree. C. for an SOC of 50%, and hence is excellent
in the input/output characteristics at low temperatures, also
providing an energy storage device module having a high energy
density.
EXAMPLE 27
[0115] FIG. 5 is an underside front view of a hybrid electric
vehicle fabricated by mounting two energy storage device modules
and an internal combustion engine. As the energy storage device
modules 81, the energy storage device modules according to Example
26 were used, which are connected to a module control circuit 82 so
as to be controlled. The hybrid vehicle is controlled by a motive
power control circuit (hybrid controller; HEVCON) 86 with respect
to the running and the energy utilization efficiency. HEVCON 86
controls an internal combustion engine 84, an inverter 85, a drive
motor 83 and a module control circuit 82 in such a way that the
input/output for each of these members is controlled according to
the running conditions. The motive power controlled by HEVCON 86 is
transmitted to drive wheels 89 through a drive shaft 87, a
differential gear 88, a clutch 811 and a clutch gear 812.
[0116] The running conditions are transmitted to HEVCON 86 by a
speed monitor 812 and the like. When the vehicle is started, the
electric power of the energy storage device modules 81 is
transformed into alternating-current electric power through the
inverter 85, and thereafter input into the drive motor 83 so as to
drive the drive motor 83. The drive motor 83 rotates the drive
wheels 89, and the vehicle can be thereby driven. According to the
signals from HEVCON 86, the module control circuit 82 makes
electric power be transferred from the energy storage device
modules 81 to the drive motor 83. When the car speed exceeds 20
km/h during running by means of the drive motor 83, a signal is
emitted from the motive power control circuit 86 to link the clutch
810 so as to crank the engine 84 by using the rotation energy from
the drive wheels 89. HEVCON 86 weighs up the signals from the car
speed monitor 812 and the condition of pushing down the
accelerator, and the power supply to the drive motor 83 is thereby
regulated, so that the number of rotations of the engine 84 can be
regulated by the drive motor 83. When the car speed is a reduced
value, the drive motor 83 operates as an electric generator to
regenerate electric power into the energy storage device module 81.
The energy storage device modules according to the present
invention can be made light in weight, and hence can improve the
gas mileage of hybrid vehicles.
[0117] In this Example, a hybrid vehicle with an internal
combustion engine mounted thereon is adopted, but a hybrid vehicle
with a fuel cell mounted thereon in place of the internal
combustion engine can also be adopted. In that case, the parts
associated with the internal combustion engine such as an engine
and the like come to be unnecessary. The energy storage device
module of the present invention can also be embodied as power
supplies for mobile objects such as pure electric vehicles and golf
carts exclusively using energy storage device modules as power
supplies. It is to be noted that the energy storage device module
of the present invention is particularly excellent in the
input/output characteristics at low temperatures so as to generate
high output power at -30.degree. C. for an SOC of 50%.
EXAMPLE 28
[0118] In this Example, the energy storage devices described in
Examples 1 to 26 and the modules using these devices are applicable
to the following power supplies and are particularly excellent in
the input/output characteristics at low temperatures so as to
generate high output power at -30.degree. C. for an SOC of 50%:
power supplies for various types of portable
information-communication equipment such as personal computers,
word processors, cordless handsets, electronic book players,
cellular phones, car phones, pagers, handy terminals, transceivers
and portable radios; power supplies for various types of portable
equipment such as portable copiers, electronic organizers,
electronic calculators, liquid crystal television sets, radios,
tape recorders, headphone stereos, portable CD players, video movie
players, electric shavers, electronic translators, voice encoders
and memory cards; electronic power supplies for household electric
appliances such as refrigerators, air conditioners, televisions,
stereos, water heaters, electric microwave ovens, dishwashers,
dryers, washers, lighting apparatuses and toys; and furthermore,
power supplies for industrial applications including medical
instruments, electric power storage systems and elevators.
Furthermore, the energy storage devices are particularly excellent
in the input/output characteristics at low temperatures so as to
generate high output power at -30.degree. C. for an SOC of 50%.
* * * * *